This 6.7X-225X zoom magnification trinocular stereo microscope head offers top-level sharp clear erect stereo images over a large zoom magnification range. It includes a 2.0X Barlow lens and two pairs of extreme widefield focusable eyepieces (WH10X/22 & WH25X/12). Its outstanding optical system ensures an easy and comfortable observation. This microscope head fits all the stands with a 3" (76mm in diameter) O-ring holder.